What do you do when you have a girl who straight up ignores you but has mad fun with your bestfriend while you three are together?

Before I start, I may sound rude but it's because I'm a little pissed off. Hope you understand.

Ok so, please don't say some beta shit like "oh just ignore them dawg, don't waste yo time thinking about them" I'm fucking alone over here while these two has the time of their lives while completely ignoring me. How will I just ignore them? This shit is wack yo. I feel unimportant and useless and that makes me angry. This is disrespect and as a man, it affects my honor.

We see each other very frequently and that can't be stopped. That's all I will say.

Also the girl gets pleasure seeing me suffer alone. Don't ask me how I know this, it's just true. So I try my best not to look like I'm affected. I try to ignore them as best I can.

I want to find a way how I can deal with this. How can I change the emotional environment?